He is a creative attacking midfielder and playmaker known for his techique, dribbling ability, vision, and accurate passing; he is also capable of playing as a supporting forward or on the wing on occasion.[3] As well as being an effective assist provider, he is also known for his goalscoring ability,[4] and he is an accurate set-piece taker.[5] Diego is also known for his trickery and ball-skills, such as his use of back-heels, feints, and overhead kicks, among an assortment of other tricks.[6]

At age six, Diego started to show his talent when training with Comercial FC in Ribeirão Preto. After joining another team, São Carlos, when he was nine, Diego decided to take trials in the hope of impressing a bigger club.[7] Diego was first signed by the São Paulo team Santos FC at the age of 12. Diego developed whilst in the Santos youth system, making his first team debut at the age of 16 in the Rio-São Paulo Championship in 2002 and in the same year he won the domestic Campeonato Brasileiro championship. He, Robinho, Elano and Alex were known as a famous group when they played for Santos.

Diego was then signed by Portuguese club FC Porto in July 2004 as a replacement for the FC Barcelona-bound Deco and was seen as his successor to Deco, but could not produce the same calibre of performances he did at Santos. Diego made his debut for Porto in a 1–1 draw against União de Leiria on 22 August 2004. On 30 October 2004, Diego scored his first goal for Porto in a 2–2 draw against Nacional. In his first season at Porto, Diego made 30 appearances, scoring two goals against Sporting Clube de Portugal and Sporting de Braga. In 2005–06, however, Diego did not maintain a stable place in the Porto team under coach Co Adriaanse and also found life difficult at Porto. He eventually left Porto for Werder Bremen.

In May 2006, Diego signed a contract with Werder Bremen until 2010 for a transfer fee of €6 million.[8]

His first match for Werder Bremen came in the DFB-Ligapokal (League Cup). Werder Bremen won the cup, beating Bayern Munich in the final on 5 August.

The 2006–07 Bundesliga season began well for Diego. He scored the first goal and set up two more for Bremen in their 4–2 win over Hannover 96, on 13 August. In his second match in the Bundesliga, he set up both goals in the 2–1 win over Bayer Leverkusen.

Thanks to his good performances in August, both in the Bundesliga and in the Ligapokal, Diego won the August Player of the Month award.[9] As the Bundesliga season went on, Diego made several amazing performances and became one of the most valuable players for Werder Bremen, along with his teammate Torsten Frings. They were called the "two motors of Bremen's midfield." In October 2006, he won a second Player of the Month award and again in December 2006. He was then named as the Best Player of the first half of the Bundesliga.

Werder Bremen finished in third place in Group A in the Champions League group stages, and they moved to the UEFA Cup, where they reached the semi-finals, beating AZ from the Netherlands in the quarter-finals, due in part to Diego's creative play.

On 15 April, Diego again played well, scoring in the 2–0 win over Borussia Dortmund. Five days later, on 20 April, Bremen played against Alemannia Aachen. Although Diego's performance was good, he did not score until stoppage time when he scored from 62.5 metres, which later was elected as goal of the year. Bremen won the game 3–1 and topped the table with 60 points.

After the 2006–07 season ended, Diego won the Bundesliga Player of the Season award organised by popular magazine kicker.[10] He received just over 50 percent of the votes. Unfortunately, his team did not win the Bundesliga after finishing third in the table, behind champions VfB Stuttgart and Schalke 04.

Diego started his season well, scoring a penalty on the first matchday. Diego gave many outstanding performances. He was crucial as Bremen got through to the Champions League's group phase. They beat Croatian club Dinamo Zagreb 3–2 in Zagreb, with Diego scoring two penalties.

On the first Champions League Group Stage matchday, Bremen lost 2–1 to Real Madrid, but Diego's performance aroused interest in Real Madrid's coach Bernd Schuster. But the stories were put to an end when Diego signed a new contract which would last until 2011.[11]

After the loss to Real Madrid, Bremen faced VfB Stuttgart, the defending German champions, at home. Werder won 4–1, with Diego leading the midfield. Later on in the season, Bremen achieved a historical 8–1 win over Arminia Bielefeld, with Diego assisting three goals and scoring one himself.

Diego's last season in Werder Bremen was his most successful. Diego scored 20 goals in total (more than his two first seasons in the club), although Bremen did finish just 10th in the Bundesliga and were knocked out of the Champions League at the group-stage.

In the UEFA Cup that season, Diego scored six goals, all in the knockout stages.

He scored against Milan the in round of 32, equalizing after 84 minutes, and assisting Claudio Pizarro in the second leg's only goal. He helped his team through the round of 16, and scored four of the six goals, and managed one assist in the quarter-final knockout of Udinese.

Diego playing for Juventus

In the semi finals, after losing 1–0 in their hometown to "North Derby" rivals Hamburger SV, Diego helped his team back in the second leg with an early equalizer to Ivica Olić's early critical goal. Later on that game, he assisted a corner to Frank Baumann's third Bremen goal. In that game, Diego received an unfortunate yellow card, preventing him from playing in the final, and with a 3–2 away win, he ended his UEFA Cup participation, leading Bremen to their first UEFA Cup final ever.

On 26 May 2009, Diego signed a five-year contract to join Juventus at the end of the season. The fee paid to Bremen by Juventus was worth €24.5 million. The price can rise by a further €2.5 million in case of the fulfillment of established sports objectives in the next five years.[13]

Diego made his Juventus debut against the Korean side Seongnam, in a game they won 3–0. In the first half, Diego made the pass to Mauro Camoranesi, whose pass followed up to a goal. Diego then scored in the second half and was subbed out at the 60th minute.[14] On his Serie A debut, he assisted Vincenzo Iaquinta's goal from a set-piece.[15] In the second fixture of the campaign, Diego recorded his first Serie A goal, scoring twice in Juventus' 3–1 victory against Roma on 30 August 2009. He also scored goals against Bologna, Fiorentina, and also against Napoli. One of his most noted assists was his backheel to Alessandro Del Piero's goal against Genoa. He has also scored in the 2010 Trofeo TIM against Milan.[16] Diego's swaggering displays he produced during his time in Bremen were met with anger and confusion from Juventus' fans; the formation did not suit him and he had a fall-out with then coach Ciro Ferrara. Juventus announced Diego would leave Juventus despite pleading to stay at the club. German clubs like VfL Wolfsburg, Bayern Munich, and his former club Werder Bremen were linked to sign him. But Werder Bremen ruled out signing him due to sporting director Klaus Allofs believing a deal to bring him back to Bremen would be "economically impossible."[17] and Diego reiterated his desire to stay.[18]

Eventually, on 27 August 2010, Diego moved from Juventus to VfL Wolfsburg for a club record transfer fee of €15.5 million, which Juve would only received €14.75 million as 5% of the transfer fee transferred to his youth clubs as solidarity contribution.[19] Following his move to Wolfsburg, Diego criticized Juventus general director Giuseppe Marotta for his exit and is the blame for letting Juventus make huge losses on some high-profile players.[20]

In his first match for VfL Wolfsburg, he scored his debut goal in a game which Wolfsburg lost 3–4 to Mainz. On 5 February 2011, Diego won a penalty for Wolfsburg. Diego took the ball from designated spot-kick taker Patrick Helmes and then hit the woodwork 10 minutes from time. Wolfsburg later lost the match by one goal and Wolfsburg's manager Steve McClaren fined him €100,000 (£86,000) for failing to follow instructions. Diego was defended by Dieter Hoeneß, claiming that Diego does not believe he should be banned for the incident.[21] He was also informed that he will be removed from the first team for Wolfsburg’s upcoming game against Hamburger SV.[22] He once again got in trouble with the management of Wolfsburg, when, on 14 May before a crucial relegation game against Hoffenheim, he left the hotel in which the team was staying when he was informed he would not be starting the game.[23] This left Wolfsburg with only six players on the bench for the game that would determine whether they would play another season in the German Bundesliga or be relegated. Wolfsburg went on to win the game 3–1 without Diego, ensuring another top flight season for the club, though Diego was fined €500,000 for his actions.[24]

After the 2010–11 season at Wolfsburg, new manager Felix Magath told Diego in May he had no future with Wolfsburg. On the last day of the transfer season, Diego joined Atlético Madrid in La Liga on a season-long loan.[25] On 10 September 2011, he made his debut for Atlético against Valencia CF.[26] He scored his first goal for Atlético in the 60th minute of a UEFA Europa League game against Celtic to make it 2–0 and made assist to Radamel Falcao in the third minute. The match resulted 2–0 win for Atlético.[27] Diego scored his first league goal in a 3–2 win over Levante UD on 20 November 2011.

As a key player for Atlético, Diego provided assists and established himself in the first team. But on 19 February 2012 against Sporting Gijón, Diego sustained a hamstring injury in the second half.[28] It would announced that Diego would be out for a month.[29] After a month out, Diego recovered from his injury and made his return to training.[30] Diego made his return against Real Zaragoza on 26 March 2012.[31]

On 9 May 2012, Diego scored the third goal on Atlético's win over Athletic Bilbao in the Europa League Final, assuring the capital side won the title for the second time in three years.[32] After the match, Diego told UEFA’s official website, "We played against a tough rival like Athletic, but we played an almost perfect match, it was a difficult match, we never said it was going to be easy. I have to thank God for this [victory]."[33]

Fellow midfielder Juanfran revealed that Diego wants to stay at Madrid rather than go back to Germany but confessed that it would be tough for the club to buy him outright.[34] Diego admitted that his time with Atlético has been "magical," stating that his time in Spain was more than what he could have hoped for: "This season was positive on both an individual and collective level and I'm delighted."[35] and made a farewell message to the club's fans, telling them about the club will be part of his life.[36] Seven months on, Diego revealed he was unaware over a permanent move to Atlético Madrid as the move never happened.[37]

Diego returned to Wolfsburg following the end of his loan spell in Madrid. Upon his return, his relationship with manager Magath continued to deteriorate, by placing him to the reserve side[38] after Magath criticised his attitude on his first training session back.[39] Despite the strained relationship between the two, he was selected by Magath in a series of pre-season friendlies in a tour of China.[40] He was told by Magath he has no future in Wolfsburg, nevertheless Diego announced that he would stay at the club, as clubs overseas had no interest signing him.[41]

Diego played his first game for the club in a 1–0 victory over Stuttgart on the opening game of the Bundesliga. In the club's first game without Magath after being sacked with only five points in eight matches (and no goals and points in the last four games), he scored his first goal and provided his first assist of the Bundesliga season in Wolfsburg's 4–1 defeat of Fortuna Düsseldorf on 27 October 2012 that ended a run of four straight defeats.[42] Following the match, Diego stated that the club are enjoying their football again and he had given a chance under new interim manager Lorenz-Günther Köstner.[43][44] Four days later in the DFB-Pokal, Diego opened the scoring before providing an assist for Bas Dost as Wolfsburg defeated FSV Frankfurt 2–0.[45] He netted a brace in Wolfsburg's 3–1 victory over Bayer Leverkusen on 11 November, bringing to an end Bayer's 11-game unbeaten run and giving Wolfsburg their first home win of the Bundesliga season.[46] Then, on 8 December 2012, Diego scored and set up the second and third goal in match, in a 3–2 win over Borussia Dortmund.[47] Throughout the 2012–13 season, Diego continued to make an impressive display for the club, scoring ten goals in thirty-seven appearance in all competitions, making him the club's top-scorer.

Ahead and ongoing of the 2013–14 season, Diego was linked back to Santos[48] and Arsenal.[49] Diego stayed in the first half of the season and scored three times in fifteen appearances. During the first half of the season, Diego's future at Wolfsburg was uncertain after he disagreed with the sporting director Klaus Allofs.[50] At this time, Diego earned the highest wages at the club.[51] The club was keen to extend Diego's contract.[52]

On 31 January 2014, Diego moved back from Wolfsburg to Atlético Madrid. He signed a contract for the rest of the 2013–14 season.[53] Prior the move, Diego desired to leave Wolfsburg in order to play in the Champions League.[54]

Diego debuted on 2 February on Atlético's victory 4–0 against Real Sociedad, scoring the match's fourth and final goal.[55] On 1 April, Diego scored from a long-range shot against FC Barcelona in the Champions League,[56] as Atlético reached the semi-finals for the first time since 1974. Atlético Madrid would reach the final of the Champions League for the second time since 1974. after beating Chelsea 3–1 to face their rival Real Madrid in their first ever Madrid derby in the Champions League final. Unfortunately for him, Diego was an unused substitute in the final, as Atlético Madrid lost 4–1.[57] Nevertheless, Diego helped the club win the La Liga to earn his team its first league title in 18 years.[58]

After being linked a move away, Diego wrote on his Instagram account, giving the Atlético Madrid supporters a farewell message, as he left the club for the second time.[59]

Upon his contract expiring at the end of the 2013–14 season, Diego was linked with a move to both Arsenal and Fenerbahçe,[60] and on 11 July 2014, Fenerbahçe confirmed a three-year deal after a medical.[2]

Diego made his international debut in April 2003 in a friendly match against Mexico. He was later included in Brazil U-23 team that competed in 2003 CONCACAF Gold Cup alongside Santos' teammate Robinho. Although Brazil compete as an under-23 team, the international appearances and goals were recorded as FIFA acknowledge the tournament as senior-team matches. He appeared five times and scored two goals as Brazil U-23 lost out to Mexico senior-team in the final.

In 2004, Diego was called up for the Brazil national squad for the Copa América 2004, and he was instrumental in securing the tournament victory for Brazil when he scored in the penalty shootout against Argentina in the final.

However, due to his decline in performance with FC Porto between 2004 and 2006, he was often left out of the Brazil squad. He was mostly playing as deputy to Kaká and was also left out of the Brazil squad for the 2006 FIFA World Cup.

He was then included in Brazil's squad for Copa América 2007, which Brazil went on to win, once again defeating Argentina in the final.

Diego also participated with Brazil U-23 team for 2008 Olympics in Beijing. Brazil went on to achieve Bronze medal with a third place finish in the tournament.

Diego is of Italian ancestry with both of his paternal great grandparents emigrating from Italy to Brazil. His paternal great grandfather, Carlo Lazzari, came from Ferrara, Italy, and his paternal great grandmother, Maria Concetta Viola, came from Naples, Italy. As a result of his Italian ancestry, Diego received his Italian passport in 2004.[66]

Diego is married to longtime girlfriend Bruna Letícia Araújo and has two children; a son (born in 2011) and a daughter (born in 2013).[67][68][69]